System for controlling motor vehicle components according to the “drive-by-wire” principle

ABSTRACT

A “drive by wire” system reverts to a safe condition if an error affecting safely is identified. The system includes a steerable wheel, a steering device, and control computers linked to sensor(s) which detect movement and position of the steering wheel. The system includes positioning devices mechanically coupled to the steerable wheel and controllable by one of the control computers and majority voting units. The positioning unit is actively controllable by its assigned control computer. The control computers determine their own condition and the condition of the system by model-based calculations, using measured values detected by the sensors and switch over from, the currently active control computer to the control computer assigned to the other positioning unit, if deviations from the model forecasts in a majority of the control computers are indicated.

FIELD OF THE INVENTION

The present invention relates to a system for controlling vehiclecomponents, e.g., for steering a vehicle, according to the “Drive byWire” principle.

BACKGROUND INFORMATION

The fundamental characteristic of a “Drive by Wire” vehicle is that adirect, mechanical connection exists neither between the foot controlsand the corresponding components (gas, brake, clutch), nor between thesteering wheel and the wheels coupled to it. The control measures takenby the driver are no longer directly converted into mechanicaldisplacements, but are picked up by sensors at the pedals and thesteering wheel, electronically processed by control computers, andtransmitted as an electrical, controlled variable to the correspondingactuators.

The advantages of a “Drive By Wire” system include, inter alia, theincrease in passive safety, since, e.g., the elimination of a steeringcolumn excludes it from intruding into the vehicle interior. Inaddition, the comfort of the vehicle can be improved, because, e.g., itis possible to freely select the restoring torque at the steering wheeland vary the transmission ratio between the steering wheel and thewheels coupled to it. There are also design advantages. Thisfacilitates, for example, the construction of right-hand/left-handsteering designs, as well as their selection, and also facilitates theconversion to driving-school vehicles or disabled-friendly vehicles.Furthermore, “Drive By Wire” systems simplify the system integration ofdevices such as a vehicle stability control system, anti-lock brakingsystem, traction control system, automatic speed control, etc., whichmeans that the costs can be correspondingly reduced.

On the other hand, a “By Wire” system has, however, the problem that atransition into a safe state is not ensured in the event of a fault inone of its components. In contrast to, e.g., conventional power-assistedsteering, which still retains the basic steering function in the eventof a fault that leads to the failure of the servo assistance of thesteering, the malfunction of a component in a “By Wire” system can havefatal consequences if design or conceptional safety measures are nottaken.

A hydraulic steering device is described in U.S. Pat. No. 4,771,846. Thehydraulic steering device is supplied with pressurized hydraulic fluidby a pump, via a proportional valve. The proportional system iscontrolled with the aid of an electromagnet, using signals picked up bya steering-angle sensor. In this context, the proportional valve iscontrolled so that the value specified by the steering-angle sensor isset at the steered wheels. In this case, it is disadvantageous that theentire steering system fails when the proportional valve ceases tooperate.

A further steering system is described in German Published PatentApplication No. 35 36 563, where the movement of a steering handwheelstarts an electric motor, using switching electronics. The electricmotor drives a pump, which is connected to working chambers of a workingcylinder. In this context, the rotational direction of the pumpdetermines the direction in which the working cylinder is displaced.This system is also not redundant and runs the risk of complete failure.

In addition, German Published Patent Application No. 40 11 947 describesa steering system for two steerable wheels, where the wheels can besteered independently of each other. The individual wheels are driven bya servomotor, which is powered by an electronic control unit. In thiscase, there is also the danger of the vehicle no longer being steerablein response to the servomotor or the electronic control unit failing.

A steering system, which controls at least two independent motors withthe aid of at least two independent control units, is described inGerman Published Patent Application No. 42 41 849. Safe operation isensured by fault monitoring and redundancy in the motors. Afault-monitoring device prevents a defective control unit fromcontrolling the steering elements. However, it is disadvantageous thatincorrect steering is triggered by any undetected faults in the controlunits.

It is an object of the present invention to provide a “Drive By Wire”system, e.g., for steering a vehicle, which passes over into a safeoperating state in the event of one of its components malfunctioning ina manner that is critical with regard to safety.

SUMMARY

This object is achieved by providing a system as described herein. Oneexample embodiment of the system of the present invention accordinglyincludes at least one steerable wheel, a steering wheel or equivalentsteering device, an odd number of more than one intercommunicatingcontrol computers which are each connected to at least one first sensordetecting a movement or actuation of the steering wheel or steeringdevice and to at least one second sensor directly or indirectlydetecting the position of the at least one steerable wheel, a firstactuator and a second actuator which are each mechanically coupled tothe at least one steerable wheel and may each be controlled by one ofthe control computers, a first voter-basis discriminator that isassigned to the first actuator, and a second voter-basis discriminatorthat is assigned to the second actuator. Each of the control computerstransmits a first signal to the first voter-basis discriminator and asecond signal different from the first signal to the second voter-basisdiscriminator. The actuator, the assigned voter-basis discriminator ofwhich receives the first signal from the majority of the controlcomputers, is actively controllable by its assigned control computer.Using model calculations and the measured values acquired by thesensors, the control computers ascertain their own state and the stateof the system and, in each case, effect a switchover from the activecontrol computer to the control computer assigned to the other actuatorif the system function shows deviations from the model expectations of amajority of the control computers.

Therefore, the system components that are critical with regard to safetyare configured with redundancy so that, in the case of a malfunctioningcomponent, the system automatically switches over to a correspondingcomponent that works correctly. In the control computers, a routine maybe implemented which allows each controlling, control computer toformulate and transmit a switchover request to the other controlcomputers, whereby the other control computers change their signalsreceived by the voting-basis discriminators, so that anothercontrol-enabled control computer assumes control in the system, by thencontrolling the actuator assigned to it.

An example embodiment of the system according to the present inventionprovides for the control computers intercommunicating via a CAN bus.This may be advantageous, since a CAN bus operates in a substantiallyfault-tolerant manner, and independently of the CPU.

Another example embodiment of the system according to the presentinvention is characterized in that the actuators each possess ahydraulic control unit having a double-acting steering cylinder, the twocylinder chambers of each steering cylinder being interconnectable by asteering bypass valve. In each case, this arrangement may allow one ofthe redundant steering cylinders to be switched on or switched off in asimple and reliable manner. In this context, the voter-basisdiscriminators control the steering bypass valves and thus establishwhich hydraulic circuit is active at any one time.

Another example embodiment of the present invention provides for thepressure in each of the two cylinder chambers of the dual-actingsteering cylinder being adjustable, using a proportional valve, aseparate pressure sensor being connected to each of the two cylinderchambers. In this context, each steering cylinder may be assigned itsown pump for providing the necessary supply pressure.

The outlet of the pump may be connected to a pressure reservoir, via anon-return valve. Therefore, the pump may not be continuously run duringthe operation of the vehicle. Along these lines, a pressure sensor maybe provided for measuring the supply pressure, the pump being limited bythe actively-controlling control computer in response to a predefinedpressure value being reached.

In addition, a branch leading into a hydraulic-fluid tank may beconnected to a pump bypass valve, between the outlet of the pump and thenon-return valve. This allows the pump to start up withoutcounterpressure from the system. In the case of an electric pump, thismay prevent high starting currents.

A further example embodiment according to the present invention providesfor one of the control computers controlling a steering-torque motorconnected to the steering wheel, in order to simulate a restoringtorque. In this context, the pressure difference between the twocylinder chambers of the double-acting steering cylinder is used as abasis for calculating the restoring torque at the steering wheel.

The system of the present invention may include a brake system, as well.The system may additionally include: a brake-pedal mechanism; a firstwheel-brake cylinder and a second wheel-brake cylinder, which eachbelong to different brake circuits that each have a hydraulic controlunit; as well as a number of third sensors corresponding to the oddnumber of more than one control computers; each third sensor detectingthe position of the brake pedal and being connected to one of thecontrol computers, so that each brake circuit is assigned a differentcontrol computer, by which the corresponding brake circuit may becontrolled according to the “Brake By Wire” principle. In this case, thecontrol computers and voting-basis discriminators present for thesteering, as well as parts of the hydraulics, may be used for the brakesystem as well.

The brake system may be divided into two brake circuits that areindependent of each other, each brake circuit having two wheel-brakecylinders, of which the one wheel-brake cylinder is assigned to a frontwheel and the other wheel-brake cylinder is assigned to a rear wheel onthe opposite side of the vehicle.

The present invention is explained in detail below with reference toFigures that represent an exemplary embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of a system according to the presentinvention, for electrohydraulically steering and braking a vehicleaccording to the “Drive By Wire” principle.

FIG. 2 is a schematic view of the components of the steering hydraulicsused in the system illustrated in FIG. 1.

FIG. 3 is a schematic view of the components of the brake hydraulicsused in the system illustrated in FIG. 1.

DETAILED DESCRIPTION

The “Drive By Wire” system schematically illustrated in the Figuresincludes two subsystems, namely, a steering system and a brake system.Therefore, the “Steer By Wire” and “Brake By Wire” subsystems differfrom a functional standpoint. The actuators for steering and braking areboth present in duplicate so that, in response to the failure of oneactuator, the system may switch over to the other.

Three intercommunicating control computers 1, 2, 3 and two voter-basisdiscriminators 4, 5, which are also referred to as “voters”, form thecenter point of the system illustrated. Each of the control computers 1,2, 3 is equipped with its own sensors 6, 9, 12; 7, 10, 13; 8, 11, 14 inorder to pick up the control taken by the driver, using the steeringwheel and the brake pedal, and to detect the steering angle of thewheels. In addition, sensors are present for detecting the power-supplystate. In this context, each of the control computers also has its ownauxiliary power supply. A CAN bus 15, which functions in a substantiallyfault-tolerant and CPU-independent manner, is used for communicationbetween control computers 1, 2, 3.

Control computers 1 and 3 have control over their own hydraulic steeringand brake circuits. Either just the circuit of control computer 1 orjust the circuit of control computer 3 is active with regard to thesteering, whereas two brake circuits may be always used. Controlcomputer 1 controls the left front (reference numeral 16) and right rearwheel-brake cylinders, while control computer 3 correspondingly controlsthe front right (reference numeral 17) and left rear wheel-brakecylinders, so that, in case a brake circuit fails, the basic functioningof the brakes may still be ensured. Reference numerals 18 and 19 eachdesignate a hydraulic control unit, to which, in addition to thewheel-brake cylinders of a brake circuit, a double-acting steeringcylinder 20 and 21 is connected, respectively.

On one hand, control computer 2 is used as a control computer for thetwo control-capable computers 1 and 3 and therefore allows, for thefirst time, a voter-basis decision in voter 4 and 5. On the other hand,it controls a steering-torque motor that simulates a restoring torque onsteering wheel 22.

Voter-basis discriminators (voters) 4, 5 control steering bypass valves23 (cf. FIG. 2) and thus stipulate, which hydraulic steering circuit iscurrently active. Each of the two voter-basis discriminators 4, 5receives a 1-bit input signal from each of the three control computers1, 2, 3. From the point of view of the specific control computer i, thetwo signals that it outputs to voter-basis discriminators 4, 5 are theinverse of each other, i.e., it either transmits a low signal (E_(1i)=0)to voter-basis discriminator 4 and a high signal (E_(2i:=E) _(1i)=1) tovoter-basis discriminator 5, or vice versa. Therefore, first subscripts(i) are omitted below.

Voter-basis discriminators 4, 5 determine their output signal A₁ and A₂in accordance with their input variables E₁ through E₃ and E₁

through E₃

from the following equations: $\begin{matrix}{A_{1}:={( {E_{1}\bigwedge E_{2}} )\bigvee( {E_{2}\bigwedge E_{3}} )\bigvee( {E_{1}\bigwedge E_{3}} )}} \\{A_{2}:={( {{E_{1}\bigwedge{E_{2}}}} )\bigvee( {{E_{2}\bigwedge{E_{3}}}} )\bigvee( {{E_{1}\bigwedge{E_{3}}}} )}}\end{matrix}$

Therefore, in each case, the hydraulic steering circuit, thecorresponding voter-basis discriminator 4 or 5 of which receives a highsignal from at least two control computers, is active. Each controlcomputer may determine which one of them is actively in control at thevery moment, by exchanging status data via CAN bus 15.

Control computers 1, 2, 3 may include microcontrollers. The controlsoftware includes a plausibility check, which identifies faults in theactuators. To this end, the driver's command, i.e., the control commandissued by the driver, using the steering wheel and/or the brake pedal,is on one hand transmitted to the specific actuator system and, on theother hand, used in model calculations in the control computers. Thevalues supplied by the model calculations are compared to the measuredvalues of the actuator system. If the measured values of the actuatorsystem are inside a specifiable tolerance range, then the actuatorsystem is functional.

The control software is configured to classify an occurring fault withregard to its effect on the entire system, i.e., it is determined if thefault or faults are tolerable or endanger the operational safety of thevehicle.

The reaction to tolerable faults may be, for example, observation and/orrecording of the fault, restoration to a known, fault-free, previousstate, or calculation of a fault-free, follow-up state with the aid of amodel.

Control computers 1, 2, 3 work with algorithms for checking orevaluating the current state of the vehicle and the “Drive By Wire”system. In particular, the checking includes test routines for theactuators, the sensory system, and the voltage supply.

A catalog of measures, which defines the reactions to all detectable,initial faults, is stored in each control computer 1, 2, 3. The systemof the present invention is configured so that, in the case of a faultthat is critical with regard to safety, it is still possible to safelypass over into a safe state. In response to the occurrence of a fatalfault, i.e., a fault endangering the safety of operation, this safestate may only be reachable when, in addition to sending optical and/oracoustic instructions to the driver, the trip is forcibly ended byactive intervention such as vehicle deceleration, by slowly andcontinuously braking.

A routine, which allows controlling computer 1 or 3 to formulate aswitchover function for switching over to the two other controlcomputers 2, 3 or 1, 2, may be implemented in the control software. Thiscauses its voter signals to be modified, so that the othercontrol-capable computer (1 or 3) assumes control. This may be necessaryfor the mentioned hydraulics test routines, which are performed in everydriving pause. The detection of a driving pause and the end of a trip islikewise based on a voter-basis decision and is initiated, in each case,by the controlling computer.

Each control computer may determine its own state, as well as that ofthe system, from the measured values picked up by the sensors and theabove-mentioned model calculations, which, e.g., with regard to thesteering, take into account the relationship between the steering-wheelangle and the angle of the wheel as a function of the pressures in thesteering-cylinder chambers. If at least two control computers determinethat the system performance is deviating from their model expectations,then they may suspend the operation of the currently active, controllingcomputer and thus force a switchover to the second hydraulic steeringcircuit, by changing their signals sent to voter-basis discriminator(voter) 4, 5.

The configuration and the function of the “Steer By Wire” and “Brake ByWire” subsystems are explained in detail below. The “Steer By Wire”subsystem includes a steering-wheel module and steering hydraulics. Inthis context, the steering-wheel module includes steering wheel 22, thesteering-torque motor, and three sensors 6, 7, 8, which each detect thesteering-wheel angle.

The steering hydraulics of each hydraulic steering circuit is dividedinto two sections (cf. FIG. 2). The first section is used to provide thesupply pressure and includes a hydraulic-fluid tank 24, a filter 25, apump 27 driven by an electric motor 26, a non-return valve 28, a pumpbypass valve (2/2 directional control valve) 29, a reservoir 30, and apressure sensor 31 for measuring the supply pressure.

Pump 27 conveys hydraulic fluid from tank 24 through non-return valve28, into reservoir 30. If a predefined, maximum supply pressure isreached, then pump 27 is limited or shut off, using suitable software.If the supply pressure falls below a predefined, minimum supplypressure, then pump 27 is switched on again. Non-return valve 28prevents the pressure from falling in the direction of tank 24. In theopen state, pump bypass valve 29 is used to allow pump 27 to start upwithout counterpressure from the system. The supply pressure built up inreservoir 31 is used for both the steering and the brake. Thus, the lineillustrated in FIG. 2 assigned the reference numeral 32 leads to thebrake hydraulics, while reference numeral 33 refers to the return linefrom the brake hydraulics to tank 24.

The second section of the steering hydraulics includes a double-actingsteering cylinder 20, a proportional valve (3/4 directional controlvalve) 34, a steering bypass valve (2/2 directional control valve) 23,and two pressure sensors 35, 36, which are each connected to one of thetwo cylinder chambers 37, 38, respectively, of steering cylinder 20.

In addition, three sensors 12, 13, 14 are present for measuring thewheel angle (cf. FIG. 1). In this context, sensors 12, 13, 14 measurethe angle of wheels 39, 40 indirectly, by sensing the position ofsteering-cylinder piston rod 41, of a tie rod 42, or of a steering rod.

If steering bypass valve 23 is closed, then a pressure may beselectively built up in each of the two steering-cylinder chambers 37,38, via proportional valve 34. Piston rod 41 of steering cylinder 20moves to the left or right as a function of the difference of these twopressures, and thus transmits the steering movement to wheels 39, 40.The pressure difference between the two steering-cylinder chambers 37,38 forms the basis for calculating the restoring torque generated atsteering wheel 22 by the steering-torque motor. Since control computer 2does not measure the pressure difference itself, this value istransmitted via CAN bus 15.

The generated restoring torque gives the driver a driving feel, which isdependent on the specific driving situation. Thus, the restoring torqueat steering wheel 22 is, for example, markedly less in the case ofdriving on a smooth, slippery road, than in the case of driving on arelatively rough or dry road. Therefore, it is possible to inform thedriver of a looming, critical driving situation in a tactile manner,using the restoring torque generated at steering wheel 22 by thesteering-torque motor. Various sensors, in particular pressure sensors,temperature sensors, slip sensors, and/or optical sensors, may be usedto detect such situations.

The pressure difference between the two cylinder chambers 37, 38 iseliminated by opening steering bypass valve 23. This switches thesteering cylinder in question to passive. In this case, the othersteering cylinder takes over the adjustment of the wheel angle, whilethe piston 43 of the passively-switched steering cylinder, which ismechanically connected to tie rod 42 by the piston rod 41 of the othersteering cylinder, follows along powerlessly.

The “Brake By Wire” subsystem is made up a brake-pedal mechanism andbrake hydraulics (cf. FIGS. 1 and 3).

The brake-pedal mechanism simulates the counterpressure of conventionalbrake hydraulics, using springs. Three springs adjusted to each otherpress against brake pedal 44 as a function of the position of brakepedal 44. This gives the driver the usual feel of conventional brakehydraulics.

In each instance, the braking hydraulics (cf. FIG. 3) assigned to one ofthe two control computers 1, 3 include: two wheel-brake cylinders, i.e.,left front (16) and right rear (116), and right front and left rear,respectively; two proportional valves (3/3 directional control valves)45, 46, which are assigned to one of the wheel-brake cylinders 16, 116,respectively; a brake bypass valve (2/2 directional control valve) 47,via which the cylinder chambers of wheel-brake cylinders 16, 116 may beinterconnected; and two pressure sensors 48, 49 connected to thecylinder chambers of wheel-brake cylinders 16, 116, respectively.

In addition, the wheel speeds are detected by two sensors. These sensorsare part of an anti-lock braking system and/or a traction controlsystem.

If steering bypass valve 47 is closed, then a different pressure may bebuilt up in each wheel-brake cylinder 16, 116, using proportional valve34. Pressure sensors 48, 49 detect these pressures. The separate controlof all four wheel-brake cylinders by control computers 1, 3 allows ananti-lock braking system to be realized.

If, however, brake bypass valve 47 is opened, then the pressure in thetwo wheel-brake cylinders 16, 116 is equalized, i.e., the two wheels(front wheel and rear wheel) are equally decelerated. Thischaracteristic is used in test routines to check the two pressuresensors 48, 49 against supply-pressure sensor 31 (cf. FIG. 2), forunacceptable deviations.

The present invention is not limited to the exemplary embodimentillustrated in the Figures. and described above. But rather, a number ofvariants making use of the inventive idea are possible, even when thearrangement deviates from the present invention. Thus, the system of thepresent invention may have, for example, an arrangement by which theratio of the steering-wheel movement to the steering movement of wheels39, 40 may be adjusted. The ratio may be varied as a function of thedriving situation, e.g., for a parking maneuver or traveling on anexpressway.

Furthermore, it is useful to combine the system with an electronicvehicle immobilizer, since the mechanical decoupling of steering wheel22 and steerable wheels 39, 40 eliminates the need for a conventionalsteering-column lock.

List of reference numerals

1 control computer

2 control computer

3 control computer

4 voter-basis discriminator (voter)

5 voter-basis discriminator (voter)

6 sensor for detecting the steering-wheel angle

7 sensor for detecting the steering-wheel angle

8 sensor for detecting the steering-wheel angle

9 sensor for detecting the position of the brake pedal

10 sensor for detecting the position of the brake pedal

11 sensor for detecting the position of the brake pedal

12 sensor for detecting the steering angle, e.g., wheel angle

13 sensor for detecting the wheel angle

14 sensor for detecting the wheel angle

15 can bus

16 front wheel-brake cylinder

17 front wheel-brake cylinder

18 hydraulic control unit

19 hydraulic control unit

20 steering cylinder

21 steering cylinder

22 steering wheel

23 steering bypass valve

24 hydraulic-fluid tank

25 filter

26 electric motor

27 pump

28 non-return valve

29 pump bypass valve

30 reservoir

31 supply-pressure sensor

32 line to the brake hydraulics

33 return line

34 proportional valve

35 pressure sensor

36 pressure sensor

37 steering-cylinder chamber

38 steering-cylinder chamber

39 wheel

40 wheel

41 steering-cylinder piston rod

42 tie rod

43 steering-cylinder piston

44 brake pedal

45 proportional valve

46 proportional valve

47 brake bypass valve

48 pressure sensor

49 pressure sensor

50 reservoir

51 electric motor

52 pump

116 rear wheel-brake cylinder

What is claimed is:
 1. A system for controlling vehicle components,comprising: at least one steerable wheel; one of a steering wheel and asteering device; an odd number of more than one intercommunicatingcontrol computers, each connected to at least one first sensorconfigured to detect one of a movement and an actuation of the one ofthe steering wheel and the steering device and connected to at least onesecond sensor configured to detect a position of the at least onesteerable wheel; a first actuator; a first voter-basis discriminatorassigned to the first actuator; a second actuator; and a secondvoter-basis discriminator assigned to the second actuator; wherein, inaccordance with model calculations and measured values acquired by thefirst sensor and the second sensor, each of the control computers isconfigured to ascertain a corresponding state and a state of the systemand, in each case, to effect a switchover from an active controlcomputer to a control computer assigned to another actuator, if thesystem function shows deviations from model expectations of a majorityof the control computers; wherein each of the control computers isconfigured to transmit a first signal to the first voter-basisdiscriminator and a second signal different from the first signal to thesecond voter-basis discriminator, the first actuator and the secondactuator mechanically and respectively coupled to the at least onesteerable wheel, the first actuator and the second actuator configuredto be controlled by one of the control computers, and one of the firstactuator and the second actuator, corresponding to the voter-basisdiscriminator that receives the first signal from a majority of thecontrol computers, configured to be actively controlled by acorresponding control computer
 15. 2. The system according to claim 1,wherein the control computers are configured to intercommunicate via aCAN bus.
 3. The system according to claim 1, wherein the controlcomputers are configured to determine a current steering-wheel angle inaccordance with the first sensors.
 4. The system according to claim 1,wherein each actuator includes a hydraulic control unit having adouble-acting steering cylinder.
 5. The system according to claim 4,further comprising a steering bypass valve configured to interconnecttwo cylinder chambers of the double-acting steering cylinder.
 6. Thesystem according to claim 4, further comprising a proportional valveconfigured to adjust specific pressure in two cylinder chambers of thedouble-acting steering cylinder.
 7. The system according to claim 4,further comprising a separate pressure sensor connected to each of twocylinder chambers of the double-acting steering cylinder.
 8. The systemaccording to claim 4, further comprising a pump assigned to thehydraulic control unit, the pump configured to provide supply pressure.9. The system according to claim 8, wherein an outlet of the pump isconnected to a pressure reservoir by a non-return valve.
 10. The systemaccording to claim 9, further comprising a branch, which includes a pumpbypass valve and is configured to empty into a hydraulic-fluid tank,connected between the outlet of the pump and the non-return valve. 11.The system according to claim 8, further comprising at least onepressure sensor configured to detect the supply pressure, the controlcomputer having active control configured to limit the pump as afunction of the detected pressure value.
 12. The according to claim 4,further comprising a steering-torque motor connected to the steeringwheel, one of the control computers configured to control thesteering-torque motor to simulate a restoring torque, a restoring torqueto be generated at the steering wheel by the steering-torque motorcalculated in accordance with a pressure difference between two cylinderchambers of the double-acting steering cylinder.
 13. The systemaccording to claim 1, further comprising a steering-torque motorconnected to the steering wheel, one of the control computers configuredto control the steering-torque motor to simulate a restoring torque. 14.The system according to claim 1, further comprising an independentpower-supply device corresponding to the control computers and the firstand second sensors.
 15. The system according to claim 1, wherein thecontrol computers are configured to implement a routine configured toallow a first controlling control computer to formulate and transmit aswitchover request to other control computers, whereby the other controlcomputers change the signals received by the voting-basisdiscriminators, so that a different control-enabled control computerassumes control in the system, by then controlling the actuator assignedto the first controlling computer.
 16. The system according to claim 15,wherein the brake-pedal mechanism includes at least one springconfigured to simulate a counterpressure of brake hydraulics.
 17. Thesystem according to claim 1, further comprising: a brake-pedalmechanism; at least one brake circuit including at least one firstwheel-brake cylinder, at least one second wheel-brake cylinder and ahydraulic control unit; at least one third sensor corresponding to theodd number of more than one control computers, each of the at least onethird sensor configured to detect a position of the brake pedal andconnected to one of the control computers, and each of the at least onethird sensor assigned a different control computer by which thecorresponding brake circuit is controllable according to a brake by wireprinciple.
 18. The system according to claim 17, wherein the at leastone brake circuit includes two brake circuits that are independent ofeach other, each brake circuit including two wheel-brake cylinders, ofwhich a first wheel-brake cylinder is assigned to a front wheel and asecond wheel-brake cylinder is assigned to a rear wheel on an oppositeside of the vehicle.
 19. The system according to claim 18, whereincylinder chambers of the two wheel-brake cylinders of a brake circuitare connectable, via a separate proportional valve, to one of a pump anda return line connected to a hydraulic-fluid tank.
 20. The systemaccording to claim 18, further comprising a steering bypass valveconfigured to interconnect cylinder chambers of the two wheel-brakecylinders of a brake circuit.
 21. The system according to claim 15,further comprising a separate pressure sensor connected to cylinderchamber of each wheel-brake cylinder.
 22. The system according to claim1, wherein the system is configured to control the vehicle componentsaccording to a drive by wire principle.